package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static{
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    //基于Redis的Stream消息队列实现异步秒杀
    /*private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";

        @Override
        public void run() {
            while (true) {
                try {
                    //1、获取消息队列中的订单消息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2、判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //3、解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4、如果获取成功，可以下单
                    handlerVoucherOrder(voucherOrder);
                    //5、ACK确认，SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlerPendingList();
                }
            }
        }

        private void handlerPendingList() {
            while (true) {
                try {
                    //1、获取消息队列中的订单消息 XREADGROUP GROUP g1 c1 COUNT 1  STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2、判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明没有消息，继续下一次循环
                        break;
                    }
                    //3、解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4、如果获取成功，可以下单
                    handlerVoucherOrder(voucherOrder);
                    //5、ACK确认，SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }*/
    //基于阻塞队列实现异步秒杀
    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    //1、获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2、创建订单
                    handlerVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }
    private void handlerVoucherOrder(VoucherOrder voucherOrder) {
            //1、获取用户
            Long userId = voucherOrder.getUserId();
            //2、获取可重入锁，指定锁的名称
            RLock lock = redissonClient.getLock("lock:order" + userId);
            //3、获取锁
            boolean isLock = lock.tryLock();//无参代表，如果没获取到锁，立马返回false
            //4、判断是否获取锁成功
            if(!isLock){
                //获取锁失败，返回错误或重试
                log.error("不允许重复下单");
                return;
            }
            try {
                //获取代理对象（事务）
                proxy.createVoucherOrder(voucherOrder);
            } finally {
                //释放锁
                lock.unlock();
            }
    }
    //基于Redis的Stream的消息队列实现异步秒杀
    /*private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId){
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1、执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        //2、判断结果是为0
        int r = result.intValue();
        if(r != 0){
            //2.1、不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3、获取代理对象
        proxy = (IVoucherOrderService)AopContext.currentProxy();

        //4、返回订单id
        return Result.ok(orderId);
    }*/
    //基于阻塞队列实现的异步秒杀
    private IVoucherOrderService proxy;
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    @Override
    public Result seckillVoucher(Long voucherId){
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1、执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        //2、判断结果是为0
        int r = result.intValue();
        if(r != 0){
            //2.1、不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2、为0，有购买资格，把下单信息保存到阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3、订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4、用户id
        voucherOrder.setUserId(userId);
        //2.5、代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6、放入阻塞队列
        orderTasks.add(voucherOrder);

        //3、获取代理对象
        proxy = (IVoucherOrderService)AopContext.currentProxy();

        //4、返回订单id
        return Result.ok(orderId);
    }
    //同步秒杀
    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //1、查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2、判断秒杀是否开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            //尚未开始
            return Result.fail("秒杀尚未开始！");
        }
        //3、判断秒杀是否已经结束
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            //尚未开始
            return Result.fail("秒杀已经结束！");
        }
        //4、判断库存是否充足
        if(voucher.getStock() < 1){
            //库存不足
            return Result.fail("库存不足！");
        }

        //加锁,synchroized锁
        //Long userId = UserHolder.getUser().getId();
        //synchronized (userId.toString().intern()) {
        //    //获取代理对象（事务）
        //    IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
        //    return proxy.createVoucherOrder(voucherId);
        //}

        //分布式锁
        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId,stringRedisTemplate);

        //获取可重入锁，指定锁的名称
        RLock lock = redissonClient.getLock("lock:order" + userId);
        //获取锁
        boolean isLock = lock.tryLock();//无参代表，如果没获取到锁，立马返回false
        //判断是否获取锁成功
        if(!isLock){
            //获取所失败，返回错误或重试
            return Result.fail("不允许重复下单");
        }
        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder){
        //5.一人一单
        Long userId = voucherOrder.getUserId();
        //5.1、查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //5.2、判断是否存在
        if(count > 0){
            //5.3、用户已经购买过了
            log.error("用户已经购买过一次！");
            return;
        }
        //6、扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId())//
                .gt("stock",0)//where id = ? and stock > 0;
                .update();
        if(!success){
            //扣减失败
            log.error("库存不足！");
            return;
        }
        //7、创建订单
        save(voucherOrder);
    }
    //同步秒杀
    /*@Transactional
    public Result createVoucherOrder(Long voucherId) {
        //5.一人一单
        Long userId = UserHolder.getUser().getId();
        //5.1、查询订单
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //5.2、判断是否存在
        if(count > 0){
            //5.3、用户已经购买过了
            return Result.fail("用户已经购买过一次！");
        }
        //6、扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId)
                .gt("stock",0)//where id = ? and stock > 0;
                .update();
        if(!success){
            //扣减失败
            return Result.fail("库存不足！");
        }
        //7、创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //7.1、订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //7.2、用户id
        voucherOrder.setUserId(userId);
        //7.3、代金券id
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);

        //8、返回订单id
        return Result.ok(orderId);
    }*/
}
